Semiconductor device

ABSTRACT

A semiconductor device reduces the impedance of a wiring for supplying the circuit excluding a data output circuit with a power source voltage or a ground voltage and of speedup of data signal transmission in the data output circuit. Additional substrates  2   a,    2   b  are on the upper surface of semiconductor chip  1.  First additional wiring layer for power source  10   d  and first additional wiring layer for ground 10 s  formed on respective additional substrates  2   a,    2   b  form prescribed conductive areas on semiconductor chip  1 . First power source wiring  40 C 1d  or first ground wiring  40 C 1s  are interconnected through additional wiring layers  10   d  and  10   s . Second power source wiring  40 C 2d  and second ground wiring  40 C 2s , which is extended in the same direction as with DQ system signal wiring  40 C DQ , forms a feedback current path. Second power source wiring  40 C 2d  and second ground wiring  40 C 2s  are disposed adjacent to DQ system signal wiring  40 C DQ .

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of co-pending Application Ser. No. 12/707,996 filed on Feb. 18, 2010, which claims foreign priority to Japanese patent application No. 2009-035546, filed on Feb. 18, 2009. The entire content of each of these applications is hereby expressly incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor device including a power source wiring and a ground wiring.

2. Description of the Related Art

In recent years, a technique that reduces unevenness in the potential of electrode pads for a power source or in the potential of electrodes pads for a ground of the semiconductor chip has been utilized. This realizes a semiconductor device with increased electric properties. In such semiconductor device, for example, a power source voltage for the electrode pads for the power source is supplied from a common power source wiring in a package substrate, and a ground voltage for the electrode pads for the ground is supplied from a common ground wiring in the package substrate. This prevents unevenness in potential.

FIG. 1 is a schematic diagram showing a semiconductor chip and its peripherals in semiconductor device related to the present invention. FIG. 2 is a longitudinal sectional view of the semiconductor device shown in FIG. 1. FIG. 3 is a diagram showing a substrate wiring of the semiconductor device viewed from a side of semiconductor chip 201. FIG. 4 is a diagram showing the substrate wiring of the semiconductor device viewed from a side of external terminals 204. FIGS. 3 and 4 show external form 201 a of the package.

In an example shown in FIGS. 1 to 4, pad row 220P including electrode pads 220 is formed on both sides of the upper surface of semiconductor chip 201 mounted on circuit board 202.

There exists a plurality of types of power sources and grounds in the semiconductor device. These types of power sources and grounds include a second power source and ground system (VDDQ and VSSQ) for mainly providing a power source potential and a ground potential for a data output circuit, and a first power source and ground system (VDD and VSS) for mainly providing the power source potential and the ground potential for the circuit excluding the data output circuit.

In a configuration of the semiconductor device shown in FIG. 1, first power source pad 2200 _(1d) is included in pad rows 220P on both sides. Likewise, first ground pad 2200 _(1s) is included in pad rows 220P on both sides. That is, the potentials of the first power source and ground system (VDD and VSS) are supplied to a wide area on the semiconductor chip. Thus, pads for the first power source and ground system (VDD pad and VSS pad) on semiconductor chip 201 may be disposed on semiconductor chip 201 in a distributed manner.

On the other hand, second power source pad 220Q_(2d) and second ground pad 220Q_(2s) are disposed adjacent to DQ system signal pads 220Q_(DQ). More specifically, potentials of the second power source and ground system (VDDQ and VSSQ) are supplied adjacent to data input and output pads from the outside to the inside of the semiconductor chip. Thus, the pads for the second power source and ground system (VDDQ pad and VSSQ pad) are disposed adjacent to the data input and output pads (DQ pads) on the semiconductor chip.

Each of the pads and each of the connection lands 230 are connected to each other by bonding wire 206. A wiring runs from each connection land 230.

In the example shown in FIGS. 1 to 4, each pad and each connection land are directly connected by the bonding wire. On the other hand, a configuration where an additional wiring layer of a power source or a ground is provided on a semiconductor chip mounted on a circuit board is disclosed in Japanese Patents Laid-Open Nos. 2004-327757 and 2003-332515. Means disclosed in these documents for routing the power source wiring or the ground wiring using the additional wiring layer provided on the semiconductor chip is useful for reducing impedances of the power source wiring and the ground wiring on the circuit board.

However, if the means disclosed in Japanese Patent Laid-Open No. 2004-327757 or 2003-332515 is used for a semiconductor device mounted with a semiconductor chip such as a DRAM, a problem arises in which speedup of the signal transmission is prevented even though impedances of the power source wiring and the ground wiring on the circuit board are reduced.

Thus, inventors of the present invention have diligently studied this problem, and thereby found that the problem arises due to the following causes.

As described above, the power source and the ground externally supplied with the potential include the first power source and ground system (VDD and VSS) mainly supplying the circuit excluding the data output circuit with the power source potential and the ground potential, and the second power source and ground system (VDDQ and VSSQ) mainly supplying the data output circuit with the power source potential and the ground potential.

Among them, the potential of the first power source and ground system (VDD and VSS) is supplied to a wide area on the semiconductor chip. Thus, the pads for the first power source and ground system (VDD pad and VSS pad) may be disposed on the semiconductor chip in a distributed manner. On the semiconductor chip with the disposition of edge pads in two rows shown in FIG. 1, for example, the pads for the first power source and ground system are disposed in the pad rows on both sides. Thus, as shown in FIGS. 3 and 4, when first power source wiring 2400 _(1d) and first ground wiring 240C_(1s) (first power source and ground system) are routed around semiconductor chip 201 on circuit board 202, the following problems arise. For example, when first power source wiring 240C_(1d) is routed as shown in FIG. 5, a problem occurs in which the wire routing involves a long distance. In addition, a problem unavoidable occurs in an area in which the width of the wire decreases, and further, there is an increase in the distance of the wire routing in order to keep the wire separate from each other. Therefore, the method of routing using the additional wiring layer as disclosed in Japanese Patent Laid-Open No. 2004-327757 or 2003-332515 is advantageous to the first power source and ground system because the impedance of the wiring can be reduced.

On the other hand, second power source pad 220Q_(2d) and second ground pad 220Q_(2s) are disposed adjacent to DQ system signal pad 220Q_(DQ).

Bonding wires 206 are extended from respective pads so as to run parallel to each other. By thus matching the direction in which bonding wires 206 extended from second power source pad 220Q_(2d) and from second ground pad 220Q_(2s) with matching the direction in which bonding wires 206 are extended from DQ system signal pads 220Q_(DQ), the second power source and ground system forms a feedback current path of the output signal, thereby reducing switching noise owing to switching of the output circuit.

However, if the second power source and ground system wirings are routed on the additional wiring layer formed on the semiconductor chip, the direction in which bonding wires 206 are extended from second power source pad 220Q_(2d) and second ground pad 220Q_(2s) and the direction in which bonding wires 206 are extended from DQ system signal pads 220Q_(DQ) become different from each other. As a result, the feedback current path of the output data signal by the second power source and ground system is distorted, and the effect of reducing switching noise decreases. That is, the switching noise increases and speedup of the signal transmission is prevented.

SUMMARY

The present invention seeks to solve one or more of the above problems, or to improve upon those problems at least in part.

A semiconductor device according to the present invention comprises: a circuit board; and a semiconductor chip mounted on the circuit board and includes a data output circuit and the circuit excluding the data output circuit. The circuit excluding the data output circuit is supplied with a first power source potential or a first ground potential from the circuit board over a first path that passes through a prescribed conductive area on the semiconductor chip. The data output circuit is supplied with a second power source potential or a second ground potential from the circuit board over a second path that passes a feedback current path of a data signal to be outputted to the circuit board from the data output circuit.

According to the present invention, the circuit excluding the data output circuit is supplied with the first power source potential or the first ground potential over the first path that passes through a prescribed conductive area on the semiconductor chip without routing the path around the semiconductor chip. Thus, the power source potential or the ground potential can be conducted through a wiring of a size that is close to that of a solid pattern and can be selected for the circuit excluding the data output circuit instead of a wiring routed around the semiconductor chip, and supplied over the linear path, thereby allowing the impedance of the wiring to be reduced. The data output circuit is supplied with the second power source potential or the second ground potential from the circuit board over the second path forming that forms the feedback current path. This reduces switching noise owing to switching of the output circuit, thereby enabling data signal transmission to be performed at higher speed.

BRIEF DESCRIPTION OF THE DRAWINGS

The above features and advantages of the present invention will be more apparent from the following description of certain preferred embodiments taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic diagram showing a semiconductor chip of a semiconductor device related to the present invention;

FIG. 2 is a longitudinal sectional view of the semiconductor device shown in FIG. 1;

FIG. 3 is a substrate wiring diagram of the semiconductor device related to the present invention (a side of the semiconductor chip);

FIG. 4 is a substrate wiring diagram of the semiconductor device related to the present invention (a side of external terminals);

FIG. 5 is a diagram illustrating a wiring from a specific external terminal to an electrode pad in the substrate wiring shown in FIG. 3;

FIG. 6 is a schematic diagram showing a semiconductor chip of a semiconductor device according to an exemplary embodiment;

FIG. 7 is a longitudinal sectional view of the semiconductor device shown in FIG. 6;

FIG. 8 is a substrate wiring diagram of the semiconductor device according to the exemplary embodiment (a side of the semiconductor chip);

FIG. 9 is a substrate wiring diagram of the semiconductor device according to the exemplary embodiment (a side of external terminals);

FIG. 10 is a block diagram showing a data output circuit and the circuit excluding the data output circuit of the semiconductor chip according to the exemplary embodiment;

FIG. 11 is a diagram illustrating a first power source wiring from a specific external terminal to an electrode pad in the substrate wiring diagram shown in FIG. 8;

FIG. 12 is a wiring diagram for a DQ system signal and a second power source and ground in the substrate wiring diagram of the exemplary embodiment;

FIG. 13 is a wiring diagram for a DQ system signal and a second power source and ground in the substrate wiring diagram related to the present invention;

FIG. 14 is a diagram showing a relationship between a prescribed DQ system signal wiring and a prescribed second ground in the substrate wiring diagram (the side of the semiconductor chip) shown in FIG. 8;

FIG. 15 is a diagram showing a relationship between the prescribed DQ system signal wiring and the prescribed second ground in the substrate wiring diagram (the side of the external terminals) shown in FIG. 9;

FIG. 16 is a diagram illustrating a method for manufacturing the semiconductor device according to the exemplary embodiment;

FIG. 17 is a diagram showing a status where an additional substrate including an additional wiring layer is stacked on the semiconductor chip shown in FIG. 16;

FIG. 18 is a diagram showing a status where the electrode pad and the additional wiring layer are connected to each other by a bonding wire on the semiconductor chip shown in FIG. 17;

FIG. 19 is a diagram showing a status where the additional wiring layer and connection lands on the circuit board are connected to each other by bonding wires on the semiconductor chip shown in FIG. 18;

FIG. 20 is a diagram showing a status where the electrode pads (other than the first power and ground) and the connection lands on the circuit board are connected to each other by the bonding wires on the semiconductor chip shown in FIG. 19;

FIG. 21 is a longitudinal sectional view of the semiconductor device according to the exemplary embodiment that is manufactured by steps shown in FIGS. 16 to 20;

FIG. 22 is a schematic diagram showing a semiconductor chip of a semiconductor device according to another exemplary embodiment; and

FIG. 23 is a longitudinal sectional view of the semiconductor device shown in FIG. 22.

FIG. 24 is a schematic diagram showing a semiconductor chip and its peripherals of said semiconductor device according to a third exemplary embodiment of the present invention;

FIG. 25 is a longitudinal sectional view of the semiconductor device shown in FIG. 24;

FIG. 26 is a block diagram showing a data output circuit and a circuit excluding the data output circuit of the semiconductor chip according to the third exemplary embodiment; and

FIG. 27 is a longitudinal sectional view of the semiconductor device according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention will be now described herein with reference to illustrative embodiments. Those skilled in the art will recognize that many alternative embodiments can be accomplished using the teachings of the present invention and that the invention is not limited to the embodiments illustrated for explanatory purposes.

First Exemplary Embodiment

Next, an exemplary embodiment will be described with reference to the drawings.

FIG. 6 is a schematic diagram showing a semiconductor chip of a semiconductor device according to the exemplary embodiment. FIG. 7 is a longitudinal sectional view of the semiconductor device shown in FIG. 6. FIG. 8 is a substrate wiring diagram of the semiconductor device viewed from a side of the semiconductor chip. FIG. 9 is a substrate wiring diagram of the semiconductor device viewed from a side of external terminals. FIG. 10 shows a block diagram of a data output circuit and the circuit excluding the data output circuit of the semiconductor chip according to the exemplary embodiment.

Note that “DQ system,” a term to be used in the following description, means a system used for data input and output, and “CA system” means a command/address system.

“First power source” and “VDD” indicate a power source (a first power supply potential) of the circuit excluding the data output circuit. “First ground” and “VSS” indicate a ground (a first ground potential) of the circuit excluding the data output circuit. “Second power source” and “VDDQ” indicate a power source (a second power supply potential) of the data output circuit. “Second ground” and “VSSQ” indicate a ground (a second ground potential) of the data output circuit.

Subscripts of respective symbols have following relationship. That is, as regards the subscripts, “CA” and “A” mean the CA system; “DQ” and “Q” mean the DQ system; “d” means a power source; “1 d” means a first power source wiring; “2 d” means a second power source wiring; “S” means a ground; “1 s” means a first ground; “2S means a second ground; “L” means a land; and “C” means a wiring.

[Configuration of the Semiconductor Device]

Then semiconductor device of this embodiment includes semiconductor chip 1 resin encapsulated by encapsulating resin 5 on the upper surface (the side of semiconductor chip 1) of circuit board 2 as shown in FIG. 7. Semiconductor chip 1 of this embodiment has a rectangular shape in planar view, and includes side 10, side 1A opposite to side 10, side 1 d connecting sides 10 and 1A, and side 1 s connecting sides 10 and 1A and opposite to side 1 d.

As shown in FIG. 10, semiconductor chip 1 has data output circuit 7 a and circuit 7 b excluding data output circuit 7 a. Circuit 7 b excluding data output circuit 7 a, for example, includes a memory core (memory cell array), an input circuit and other peripheral circuits (e.g., PLL, DLL, booster circuit, etc.).

On the upper surface (the side of semiconductor chip 1) of circuit board 2, there are formed connection lands 30 and signal wiring 40W as shown in FIG. 8. On the other hand, on the back surface (the side of external terminals 4) of circuit board 2, there are formed external terminals 4 and signal wiring 40W as shown in FIG. 9. Vias 3 are formed in circuit board 2 so as to penetrate circuit board 2. Signal wiring 40W on the upper surface of circuit board 2 electrically connects connection lands 30 and vias 3. Signal wiring 40W on the back surface of circuit board 2 electrically connects external terminals 4 and vias 3. Thus, connection lands 30 and external terminals 4 are electrically connected to each other.

Additional substrate 2 a is provided on the upper surface of semiconductor chip 1. First additional wiring layer for ground 10 s is formed on the upper surface of additional substrate 2 a. Additional substrate 2 b is further provided on additional substrate 2 a. First additional wiring layer for power source 10 d is formed on the upper surface of additional substrate 2 b. Thus, in a case of the semiconductor chip shown in FIGS. 6 and 7, both first additional wiring layer for power source 10 d and first additional wiring layer for ground 10 s are stacked on semiconductor chip 1, making up additional wiring layers on layers that are different from each other. Note that first additional wiring layer for power source 10 d and first additional wiring layer for ground 10 s, which are solid patterns, form prescribed conductive areas on semiconductor chip 1. As shown in FIG. 21, the additional substrate formed on the upper surface of semiconductor chip 1 may be one additional substrate (multilayer board) 2 c where both first additional wiring layer for ground 10 s and first additional wiring layer for power source 10 d are formed.

Semiconductor chip 1 includes electrode pads 20, which are electrically connected to respective connection lands 30 by bonding wires 6. Electrode pads 20 are disposed in single lines on both sides and make up DQ system pad row 20Q and CA system pad row 20A, respectively. That is, DQ system pad row 20Q and CA system pad row 20A are disposed between the conductive area, including additional substrates 2 a and 2 b, and edges of semiconductor chip 1.

On the other hand, on circuit board 2, there are provided connection lands 30 provided corresponding to respective electrode pads 20 of DQ system pad row 20Q and CA system pad row 20A, and connection lands 30L_(1d) corresponding to first additional wiring layer for power source 10 d and connection land 30L_(1s) corresponding to first additional wiring layer for ground 10 s.

[Relationship of Electric Connection]

Next, a relationship of electric connection between data output circuit 7 a, circuit 7 b excluding data output circuit 7 a, each electrode pad 20, each connection land 30, each power source wiring and each ground wiring will be described with reference to FIG. 6. Note that DQ system pad row 20Q is for data input and output, and may also be referred to as a data input and output system pad row or a first pad row. CA system pad row 20A is for command/address, and may also be referred to as a command/address system pad row or a second pad row.

-   -   Data output circuit

Data output circuit 7 a is connected to second power source pad 20W_(2d),

DQ system signal pad 20Q_(DQ) and second ground pad 20Q_(2s). As will be described later, data output circuit 7 a is supplied with a second power source potential and a second ground potential from second power source wiring 40C_(2d) and second ground wiring 40C_(2s).

-   -   Circuit excluding data output circuit

Circuit 7 b is connected to first power source pad 20Q_(1d), first ground pad 20Q_(1s) and CA system signal pad 20A_(CA). As will be described later, circuit 7 b is supplied with a first power source potential from first power source wiring 40C_(1d) through first additional wiring layer for power source 10 d, and with a first ground potential from first ground wiring 40C_(1s) through first additional wiring layer for ground 10 _(s).

-   -   DQ system pad row—connection pad—DQ system signal wiring, second         power source/ground wiring

First, the connection relationship between DQ system pad row 20Q, connection land 30, and the DQ system signal wiring or the second power source/ground wiring will be described.

DQ system pad row 20Q is formed at side 1Q of semiconductor chip 1. DQ system pad row 20Q includes first power source pad 20Q_(1d), second power source (VDDQ) pad 20Q_(2d), DQ system signal pad 20Q_(DQ), second ground (VSSQ) pad 20Q_(2s), and first ground pad 20Q_(1s). Among these pads, those to be connected to connection lands 30 are connected to connection lands 30 disposed on side 1Q. Each electrode pad 20 will hereinafter be described in turn starting from upper disposed one in FIG. 6.

First power source pad 20Q_(1d) is connected to first additional wiring layer for power source 10 d by bonding wire 6. Second power source pad 200 _(2d) is connected to second connection land for power source 30L_(2d) by bonding wire 6. Second connection land for power source 30L_(2d) is connected to second power source wiring 40C_(2d).

DQ system signal pad 20Q_(DQ) is connected to connection land for DQ system signal 3OL_(DQ) by bonding wire 6. Connection land for DQ system signal 3OL_(DQ) is connected to DQ system signal wiring 40C_(DQ).

Second ground pad 200 _(2s) is connected to second connection land for ground 30L_(2s) by bonding wire 6. Second connection land for ground 30L_(2s) is connected to second ground wiring 40C_(2s).

First ground pad 20Q_(1s) is connected to first additional wiring layer for ground 10 s by bonding wire 6.

Note that the direction in which second power source wiring 40C_(2d) is extended from second connection land for power source 30L_(2d) and the direction in which second ground wiring 40C_(2s) is rextended from second connection land for ground 30L_(2s) are identical to the direction in which DQ system signal wiring 40C_(DQ) is extended from connection land for DQ system signal 30L_(DQ). Thus, second power source wiring 40C_(2d) and second ground wiring 40C_(2s) form a feedback current path to DQ system signal wiring 40C_(DQ), thereby reducing switching noise owing to switching of the output circuit.

Both second power source wiring 40C_(2d) and second ground wiring 40C_(2s) are preferably disposed adjacent to DQ system signal wiring 40C_(DQ). Such adjacent disposition can increase mutual inductances of second power source wiring 40C_(2d) and second ground wiring 40C_(2s) with respect to DQ system signal wiring 40C_(DQ). As a result, the effective inductance value of DQ system signal wiring 40C_(DQ) is further reduced, thereby allowing low noise and enabling signal transmission to be performed at higher speed.

-   -   CA system pad row—connection pad—each wiring

Next, a connection relationship between CA system pad row 20A, connection land 30 and each wiring will be described.

CA system pad row 20A is formed at side 1A. CA system pad row 20A includes first power source pad 200 _(1d), CA system signal pad 20A_(CA) and first ground pad 20Q_(1s). Among these pads, those to be connected to connection land 30 are connected to connection lands 30 disposed at side 1A. Each electrode pad 20 will be described in turn starting from upper disposed one in FIG. 6.

First power source pad 200 _(1d) is connected to first additional wiring layer for power source 10 d by bonding wire 6.

CA system signal pad 20A_(CA) is connected to connection land for CA system signal 30L_(CA) by bonding wire 6. Connection land for CA system signal 30L_(CA) is connected to CA system signal wiring 40C_(CA).

First ground pad 20Q_(1s) is connected to first additional wiring layer for ground 10 s by bonding wire 6.

-   -   First power source wiring—connection land—additional wiring         layer

Next, a disposition relationship between first power source wiring 400 _(1d), first connection land for power source 30L_(1d) and first additional wiring layer for power source 10 d will be described.

First connection land for power source 30L_(1d) is formed at side 1 d of semiconductor chip 1. First power source wiring 400 _(1d) is connected to first connection land for power source 30L_(1d). First connection land for power source 30L_(1d) and first power source wiring 400 _(1d) are solid patterns. First connection lands for power source 30L_(1d) are connected to first additional wiring layer for power source 10 d by bonding wires 6.

-   -   First ground wiring—connection land—additional wiring layer

Next, a disposition relationship between first ground wiring 40C_(1s), first connection land for ground 30L_(1s) and first additional wiring layer for ground 10 s will be described.

First connection land for ground 30L_(1s) is formed at side 1 s of semiconductor chip 1. First ground wiring 40C_(1s) is connected to first connection land for ground 30L_(1s). First connection land for ground 30L_(1s) and first ground wiring 40C_(1s) are solid patterns. First connection lands for ground 30L_(1s) are connected to first additional wiring layer for ground 10 s by bonding wires 6.

Thus, in this exemplary embodiment, first power source wiring 400 _(1d) and ground wiring 40C_(1s) are not directly connected to electrode pad 20, but are connected through additional wiring layers 10 d and 10 s instead.

[Operation of Semiconductor Device]

Next, an operation of the semiconductor device with the aforementioned configuration will be described with reference to FIGS. 11 to 15.

FIG. 5 is, as described above, a diagram illustrating the wiring from a specific external terminal to an electrode pad in substrate wiring diagram shown in FIG. 3. FIG. 11 is a diagram illustrating a wiring from a specific external terminal to an electrode pad in the substrate wiring diagram shown in FIG. 8. FIG. 12 is a wiring diagram about a DQ system signal and a second power source/ground in the substrate wiring diagram of the exemplary embodiment. FIG. 13 is a wiring diagram about a DQ system signal and a second power source/ground in a substrate wiring diagram of an art related to the present invention for the sake of comparison. FIG. 14 is a diagram showing a relationship between the prescribed DQ system signal wiring and the prescribed second ground in the substrate wiring diagram (the side of semiconductor chip 1) shown in FIG. 8. FIG. 15 is a diagram showing a relationship between the prescribed DQ system signal wiring and the prescribed second ground in the substrate wiring diagram (the side of external terminal 4) shown in FIG. 9.

First, FIGS. 5 and 11 will be compared with each other and current path P from the specific external terminal to the electrode pad in the substrate wiring diagram will be described.

Current path P of the art related to the present invention shown in FIG. 5 is provided according to the following order:

-   -   [1] External terminal 204;     -   [2] Substrate wiring pattern (first power source wiring         240C_(1d) including a part with a reduced trace width (part A in         the diagram) and a long and narrow pattern indicated with a         broken line (part B in the diagram));     -   [3] Connection land 230;     -   [4] Bonding wire 206; and     -   [5] Electrode pad 220.

On the other hand, current path P′ of this exemplary embodiment shown in FIG. 11 is provided according to the following order:

-   -   [1′] External terminal 4;     -   [2′] Substrate wiring pattern (first power source wiring         40C_(1d) with a size close to that of a solid pattern, excluding         a part of a decreased trace width (part A′ in the diagram));     -   [3′] Connection land 30L_(1d);     -   [4′] Bonding wires 6;     -   [5′] First additional wiring layer for power source 10 d (solid         pattern);     -   [6′] Bonding wire 6; and     -   [7′] Electrode pad 20.

According to the configuration shown in FIG. 5, there exist the part with a reduced trace width (part A in the diagram) and the long and narrow pattern indicated with the broken line (part B in the diagram) in the aforementioned current path P in [2] substrate wiring pattern. On the other hand, a trace for current path P′ excludes the part of the decreased trace width (part A′ in the diagram) and the long and narrow trace part, and has a size that is close to that of a solid pattern in [2′] substrate wiring pattern shown in FIG. 11. The wiring impedance on the substrate in the configuration shown in FIG. 11 therefore becomes smaller than that shown in the art related to the present invention shown in FIG. 5.

According to the configuration shown in FIG. 11, since [5′] first additional wiring layer for power source 10 d is also a solid pattern, the impedance thereof is smaller than that of the substrate wiring pattern that is not a solid pattern. Furthermore, according to the configuration shown in FIG. 11, [3′] connection land 30L_(1d) and [5′] first additional wiring layer for power source 10 d are connected by [4′] bonding wires 6. The plurally prepared bonding wires have an impedance smaller than that of a single bonding wire.

According to the configuration shown in FIG. 5, external terminal 204 and electrode pad 220 are connected by the wiring that detours around semiconductor chip 201. On the other hand, since first additional wiring layer for power source 10 d which is a prescribed conductive area on semiconductor chip 1 is routed, the circuit excluding the data output circuit is supplied with the first power source potential and the first ground potential over first path R1, which is a straight current path, according to the configuration of FIG. 11. Thus, the conductor length from external terminal 4 to electrode pad 20 according to the present invention is shorter than that of the art related to the present invention. Therefore, the present invention allows the external terminal and electrode pad to be connected with an impedance smaller than that of the art related to the present invention.

Next, the disposition relationship between the DQ system signal wiring, the second power source wiring and the second ground wiring will be described using FIGS. 12 and 13. Note that second power source wiring 400 _(2d) and second ground wiring 40C_(2s) are collectively illustrated in FIG. 12 for the simplicity sake. Likewise, second power source wiring 2400 _(2d) and second ground wiring 240C_(2s) are collectively illustrated in FIG. 13.

In the configuration of this exemplary embodiment shown in FIG. 12, the data output circuit is supplied with the second power source potential or the second ground potential from circuit board 2 over second path R2 that forms a feedback current path of a data signal to be outputted to circuit board 2 from the data output circuit. Thus, according to this exemplary embodiment, second path R2 including second power source wiring 400 _(2d) and second ground wiring 40C_(2s) are wired so as to be shortened to adjoin the DQ system signal wiring 40C_(DQ) in the same direction, thereby allowing the effective inductance to be reduced.

On the other hand, in Japanese Patent Laid-Open No. 2004-327757, any power source wiring and ground wiring are routed on an additional wiring layer. If this were applied to the present invention, second power source wiring 2400 _(2d) and second ground wiring 240C_(2s) would be routed using first additional wiring layer for power source 10 d and first additional wiring layer for ground 10 s in the same manner as with first power source wiring 400 _(1d) and first ground wiring 40C_(1s) of the exemplary embodiment, as shown in FIG. 13. Thus, in the configuration shown in FIG. 13, second power source wiring 2400 _(2d) and second ground wiring 240C_(2s) are arranged apart from DQ system signal wiring 240C_(DQ), and not adjacent to each other.

Here, effective inductance values are calculated by simulating the configuration of this exemplary embodiment shown in FIG. 12 and on the configuration shown in FIG. 13. A result in which the configuration shown in FIG. 12 can reduce the effective inductance value to about a quarter with respect to the configuration shown in FIG. 13 has been obtained. Thus, the configuration shown in FIG. 12 wires second path R2, i.e. return path, adjacent to DQ system signal wiring 40C_(DQ), thereby allowing prevention of a drop in voltage and an increase in noise. This enables signal transmission to be performed at higher speed.

Both second power source wiring 400 _(2d) and second ground wiring 40C_(2s) are preferably disposed adjacent to DQ system signal wiring 40C_(DQ). Such adjacent disposition allows mutual inductances of second power source wiring 40C_(2d) and second ground wiring 40C_(2s) with respect to DQ system signal wiring 40C_(DQ) to be increased. As a result, the effective inductance value of DQ system signal wiring 40C_(DQ) is further reduced, thereby allowing low noise. Therefore this enables signal transmission to be performed at higher speed.

Next, a relationship between the prescribed DQ system signal wiring and the prescribed second ground wiring will be described using FIGS. 14 and 15.

The present invention adopts a configuration in which the second power source/ground system (VDDQ and VSSQ) are extended from the semiconductor chip so that the second power source/ground system can run parallel to the output data signal. This can realize a configuration of the circuit board where the wiring of the second power source/ground system (VDDQ and VSSQ) runs through the position that is closer to the wiring of the output data signal, in comparison with a case where the second power source/ground system is routed using the additional wiring layer (the configuration as shown in FIG. 13). As a result, the effective inductance value of the DQ system signal wiring is further reduced, thereby enabling signal transmission to be performed at higher speed.

[Process for Manufacturing Semiconductor Device]

Next, a process for manufacturing the semiconductor device according to the present invention will be described with reference to FIGS. 16 to 20.

As shown in FIG. 16, semiconductor chip 1 where CA system pad row 20A and DQ system pad row 20Q are formed is mounted face up (circuit side facing up) on circuit board 2.

Next, as shown in FIG. 17, first additional wiring layer for power source 10 d and first additional wiring layer for ground 10 s are formed on semiconductor chip 1. Note that, in this exemplary embodiment, additional substrate 2 a is provided on semiconductor chip 1, and additional substrate 2 b is further provided on additional substrate 2 a in a stacked manner. First additional wiring layer for ground 10 s is formed on the upper surface of additional substrate 2 a, and first additional wiring layer for power source 10 d is formed on additional substrate 2 b.

Next, as shown in FIG. 18, first power source pad 200 _(1d) and first additional wiring layer for power source 10 d are connected to each other by bonding wire 6. First ground pad 20Q_(1s) and first additional wiring layer for ground 10 s are also connected to each other by bonding wire 6.

Next, as shown in FIG. 19, arbitrary positions on first additional wiring layer for power source 10 d and first connection lands for power source 30L_(1d) on circuit board 2 are connected to each other by bonding wires 6. Likewise, arbitrary positions on first additional wiring layer for ground 10 s and first connection lands for ground 30L_(1s) on circuit board 2 are connected to each other by bonding wires 6.

Next, as shown in FIG. 20, DQ system pad row 20Q and connection lands 30 (including connection land for DQ system signal 3OL_(DQ), second connection land for power source 30L_(2d) and second connection land for ground 30L_(2s)) are connected to each other by bonding wire 6. Likewise, CA system pad row 20A and connection lands 30 (including connection land for CA system signal 30L_(CA)) are connected to each other by bonding wire 6.

Lastly, the side of circuit board 2 on which semiconductor chip 1 and additional wiring layers 10 d and 10 s are stacked is encapsulated with encapsulating resin 5 (molding), and solder balls (e.g., comprising Sn—Ag—Cu) to serve as external terminals 4 are formed on the side of circuit board 2 opposite to the side encapsulated with encapsulating resin 5. The semiconductor device according to the present invention as shown in FIG. 7 has thus been completed.

Second Exemplary Embodiment

Next, FIG. 22 shows a schematic view of semiconductor chip of a semiconductor device according to another exemplary embodiment. FIG. 23 shows a longitudinal sectional view of the semiconductor device shown in FIG. 22.

The semiconductor device according to the first embodiment shown in FIGS. 6 and 7 adopts the configuration where additional substrate 2 a is provided on semiconductor chip 1 and additional substrate 2 b is provided in a stacked manner on additional substrate 2 a. In this configuration, first additional wiring layer for ground 10 s is formed on the upper surface of additional substrate 2 a, and first additional wiring layer for power source 10 d is formed on additional substrate 2 b. The semiconductor device according to the first exemplary embodiment thus adopts the configuration where the additional wiring layers are formed on the two stacked additional substrates, respectively.

On the other hand, in a configuration shown in FIGS. 22 and 23, first additional wiring layer for ground 10 s and first additional wiring layer for power source 10 d are formed in planar fashion on the upper surface of one additional substrate 2 a. First additional wiring layer for ground 10 s and first additional wiring layer for power source 10 d are thus disposed on the same plane of semiconductor chip 1. First additional wiring layer for ground 10 s is formed at a side near first connection land for ground 30L_(1s). First additional wiring layer for power source 10 d is formed at a side near first connection land for power source 30L_(1d). Note that, since the configuration is similar to that of the semiconductor device according to the first exemplary embodiment, a detailed description is omitted.

Third Exemplary Embodiment

A configuration shown in FIGS. 24 to 26 is different in that second semiconductor chip 1 b is provided between semiconductor chip 1 (first semiconductor chip 1 a) and additional wiring substrate 2 a compared to the semiconductor device of the first exemplary embodiment shown in FIGS. 6, 7 and 10. More specifically, in a semiconductor device of this exemplary embodiment, second semiconductor chip 1 b is provided on first semiconductor chip 1 a disposed on wiring substrate 2. Additional substrate 2 a is provided on second semiconductor chip 1 b. Additional substrate 2 b is further provided stacked on this additional substrate 2 a. First semiconductor chip 1 a includes electrode pads 20 a, as with the first exemplary embodiment. These electrode pads 20 a include CA system signal pads 20ACAa connected to other circuit 7 ba excluding data output circuits 7 aa provided on semiconductor chip 1 a, first power source pads 20Q1 da supplying other circuit 7 ba with a potential of one side of a first power source potential, first ground pads 20Q1 sa supplying other circuit 7 ba with a potential of the other side of the first power source potential, DQ system signal pads 20QDQa connected to respective data output circuits 7 aa provided on first semiconductor chip 1 a, second power source pads 20Q2 da supplying data output circuits 7 aa with a potential of one side of a power source voltage, and second ground pads 20Q2 sa supplying data output circuits 7 aa with the other side of the power source potential. Each of first power source pads 20Q1 da is connected to first additional wiring layer for power source 10 d on additional substrate 2 b through corresponding bonding wire 6. Each of first ground pads 20Q1 sa is connected to first additional wiring layer for ground 10 s on additional substrate 2 a through corresponding bonding wire 6. On the other hand, each of CA system signal pads 20ACAa is connected to corresponding CA system signal wiring 40CCA through corresponding connection land 30 provided on wiring substrate 2 using corresponding bonding wire 6. Each of DQ system signal pads 20QDQa is connected to corresponding DQ system signal wiring 40CDQ through corresponding connection land 30 provided on wiring substrate 2 using corresponding bonding wire 6. Second power source pad 20Q2 da is connected to corresponding second power source wiring 40C2 d through corresponding connection land 30 provided on wiring substrate 2 using corresponding bonding wire 6. Second ground pad 20Q2 sa is connected to corresponding second ground wiring 40C2 s through corresponding connection land 30 provided on wiring substrate 2 using corresponding bonding wire 6.

On the other hand, second semiconductor chip 1 b includes data output circuit 7 ab and other circuit 7 bb excluding the data output circuit. Second semiconductor chip 1 b includes electrode pads 20 a. These electrode pads 20 a include CA system signal pads 20ACAb connected to other circuit 7 bb excluding data output circuits 7 ab provided on semiconductor chip 1 b, first power source pads 20Q1 db supplying other circuit 7 bb with the potential of one side of the first power source potential, first ground pads 20Q1 sb supplying other circuit 7 bb with the potential of the other side of the first power source potential, DQ system signal pads 20QDQb connected to respective data output circuits 7 ab provided on second semiconductor chip 1 b, second power source pads 20Q2 db supplying data output circuits 7 ab with the potential of one side of the power source voltage, and second ground pads 20Q2 sb supplying data output circuits 7 ab with the other side of the power source potential. Each of first power source pads 20Q1 db is connected to first additional wiring layer for power source 10 d on additional substrate 2 b through corresponding bonding wire 6. Each of first ground pads 20Q1 sb is connected to first additional wiring layer for ground 10 s on additional substrate 2 a through corresponding bonding wire 6. On the other hand, each of CA system signal pads 20ACAb is connected to corresponding CA system signal wiring 40CCA through corresponding connection land 30 provided on wiring substrate 2 using corresponding bonding wire 6. Each of DQ system signal pads 20QDQb is connected to corresponding DQ system signal wiring 40CDQ through corresponding connection land 30 provided on wiring substrate 2 using corresponding bonding wire 6. Second power source pad 20Q2 db is connected to corresponding second power source wiring 40C2 d through corresponding connection land 30 provided on wiring substrate 2 using corresponding bonding wire 6. Second ground pad 20Q2 sb is connected to corresponding second ground wiring 40C2 s through corresponding connection land 30 provided on wiring substrate 2 using corresponding bonding wire 6.

Note that, in FIGS. 24 and 25, the present invention is applied to both first semiconductor chip 1 a and second semiconductor chip 1 b. Instead, it may be configured such that the present invention is only applied to any one of the semiconductor chips. For example, a DRAM may be used for first semiconductor chip 1 a; a logic, a flash memory or the like may be used for second semiconductor chip 1 b.

Fourth Exemplary Embodiment

According to a configuration shown in FIG. 27, third semiconductor chip 1 c, which is a flip chip, is mounted between wiring substrate 2 and first semiconductor chip 1 a of the first exemplary embodiment. In FIG. 27, semiconductor chip 1 c is connected to wiring pattern 40P on wiring substrate 2 using bump 50 (ex. including solder). On the other hand, in FIG. 26, first semiconductor chip 1 a is connected to additional wiring layers (10 d and 10 s) on additional substrate (2 a and 2 b) and connection lands 30 on wiring substrate 2 using bonding wire 6, as with the first exemplary embodiment. In FIG. 27, a DRAM may be used for first semiconductor chip 1 a, and an RF chip or the like may be used for second semiconductor chip 1 b.

Although a DRAM is exemplified as the semiconductor device in the above description, the present invention is not limited to this. For example, the present invention can be applied to a logic circuit where a data output circuit and the circuit are separately supplied with respective power sources.

It is apparent that the present invention is not limited to the above embodiments, but may be modified and changed without departing from the scope and spirit of the invention. 

What is claimed is:
 1. A device comprising: a substrate including first and second power supply terminals supplied with first and second power supply voltages, respectively; a semiconductor chip mounted on the substrate and including first and second side edges that cross to each other, first and second power supply pads that are arranged in line along the first side edge; and a first additional conductive layer formed over the semiconductor chip; the first additional conductive layer being configured to receive the first power supply voltage beyond the second side edge of the semiconductor chip from the first power supply terminal, the first power supply pad of the semiconductor chip being configured to receive the first power supply voltage from the first additional conductive layer, and the second power supply pad of the semiconductor chip being configured to receive the second power supply voltage beyond the first side edge of the semiconductor chip from the second power supply terminal.
 2. The device as claimed in claim 1, wherein the semiconductor chip includes a first circuit configured to operate on the first power supply voltage and a second circuit configured to operate on the second power supply voltage.
 3. The device as claimed in claim 1, wherein the substrate includes a first area running along the first side edge of the semiconductor chip and a second area running along the second side edge of the semiconductor chip, the first power supply terminal of the substrate is disposed in the second area of the substrate, and the second power supply terminal of the substrate is disposed in the first area of the substrate.
 4. The device as claimed in claim 3, wherein the second area is smaller in length along a direction, in which the second side edge of the semiconductor chip extends, than the second side edge.
 5. The device as claimed in claim 1, further comprising: a first power supply path connecting the first power supply terminal of the substrate to the first additional conductive layer and including a first bonding wiring that is elongated across the second side edge of the semiconductor chip, and a second power supply path connecting the second power supply terminal of the substrate to the second power supply pad of the semiconductor chip and including a second bonding wiring that is elongated across the first side edge of the semiconductor chip.
 6. The device as claimed in claim 1, wherein the substrate includes a signal terminal, the semiconductor chip includes a signal pad that is arranged in line with the first and second power supply pads along the first side edge of the semiconductor chip, the signal pad of the semiconductor chip is configured to receive an input signal beyond the first side edge of the semiconductor chip from the signal terminal of the substrate.
 7. The device as claimed in claim 6, wherein the signal pad of the semiconductor chip is configured to supply an output signal to the signal terminal of the substrate beyond the first side edge of the semiconductor chip.
 8. The device as claimed in claim 6, wherein the semiconductor chip includes a first circuit configured to operate on the first power supply voltage and a second circuit configured to operate on the second power supply voltage and the second circuit is coupled to the signal pad of the semiconductor chip to receive the input signal.
 9. The device as claimed in claim 1, wherein the substrate includes third and fourth power supply terminals supplied with third and fourth power supply voltages, respectively, the semiconductor chip includes a third side edge opposite to the second side edge and third and fourth power supply pads that are arranged in line with the first and second power supply pads along the first side edge, the device further comprises a second additional conductive layer formed over the semiconductor chip and insulated from the first additional conductive layer, and wherein the second additional conductive layer is configured to receive the third power supply voltage beyond the third side edge of the semiconductor chip from the third power supply terminal, the third power supply pad of the semiconductor chip is configured to receive the third power supply voltage from the second additional conductive layer, and the fourth power supply pad of the semiconductor chip is configured to receive the fourth power supply voltage beyond the first side edge of the semiconductor chip from the fourth power supply terminal to the fourth power supply pad.
 10. A device comprising: a semiconductor chip including a first side edge elongated in a first direction, a second side edge elongated in a second direction that is substantially perpendicular to the first direction, and first and second power supply pads that are arranged in line in the first direction; a substrate including a first area on which the semiconductor chip is mounted and second and third areas, the first and second areas being arranged in line in the first direction, the first and third areas being arranged in line in the second direction, the substrate further including a first power supply terminal disposed in the second area and a second power supply terminal disposed in the third area, the first and the second power supply terminals being configured to be supplied respectively with first and second power supply voltages; an additional conductive layer formed over the semiconductor chip; a first power supply path connecting the first power supply terminal of the substrate to the additional conductive layer to convey the first power supply voltage to the additional conductive layer; a second power supply path connecting the additional conductive layer to the first power supply pad of the semiconductor chip to convey the first power supply voltage to the first power supply pad; and a third power supply path connecting the second power supply terminal of the substrate to the second power supply pad of the semiconductor chip to convey the second power supply voltage to the second power supply pad.
 11. The device as claimed in claim 10, wherein the semiconductor chip includes a first circuit configured to operate on the first power supply voltage and a second circuit configured to operate on the second power supply voltage.
 12. The device as claimed in claim 10, wherein the first power supply path includes a first bonding wiring elongated across the second side edges of the semiconductor chip, and the third power supply path includes a second bonding wiring elongated across the first side edges of the semiconductor chip.
 13. The device as claimed in claim 10, wherein the semiconductor chip includes a signal pad arranged in line in the first direction with the first and the second power supply pads, and the substrate includes a signal terminal disposed in the third area and supplied with an input signal, and the device further comprises a signal path connecting the signal terminal of the substrate to the signal pad of the semiconductor chip to convey the input signal to the signal pad.
 14. The device as claimed in claim 13, wherein the semiconductor chip includes a first circuit configured to operate on the first power supply voltage and a second circuit configured to operate on the second power supply voltage and the second circuit is coupled to the signal pad of the semiconductor chip to receive the input signal.
 15. The device as claimed in claim 13, wherein the first power supply path includes a first bonding wiring elongated across the second side edges of the semiconductor chip, the third power supply path includes a second bonding wiring elongated across the first side edges of the semiconductor chip, and the signal path includes a third bonding wiring elongated across the first side edge of the semiconductor substrate.
 16. A device comprising; a substrate including a first terminal configured to be supplied with a first power supply voltage; a semiconductor chip mounted on the substrate and including a plurality of pads arranged in line in a first direction, the pads including a first power supply pad; an additional conductive layer formed over the semiconductor chip so that the additional conductive layer is on a side opposite to the substrate, the additional conductive layer being vertically away from and electrically coupled to the first power supply pad of the semiconductor chip; and a first power supply path elongated in the first direction and connecting the first power supply terminal of the substrate to the additional conductive layer to convey the first power supply voltage to the first power supply pad with an intervention of the additional conductive layer.
 17. The device as claimed in claim 16, wherein the first power supply path includes a bonding wiring.
 18. The device as claimed in claim 16, wherein the substrate includes a second power supply terminal configured to be supplied with a second power supply voltage, and the pads of the semiconductor chip includes a second power supply pad, and the device further comprises a second power supply path elongated in a second direction, that is substantially perpendicular to the first direction, and connecting the second power supply terminal of the substrate to the second power supply pad of the semiconductor chip to convey the second power supply voltage to the second power supply pad.
 19. The device as claimed in claim 18, wherein the first power supply path includes a fist bonding wiring and the second power supply path includes a second bonding wiring. 